We studied the possibility and safety of a new approach to breast-feeding infants with phenylketonuria (PKU). We compared a group of PKU infants being breast-fed according to our new protocol with a group of PKU infants receiving formula only. The breast-fed group consisted of nine infants born between 1994 and 1999 being breast-fed at the time of diagnosis. The formula-fed group consisted of nine PKU infants, born between 1988 and 1997. In the breast-fed group, feedings alternated between breast-feeding and phenylalanine (Phe)-free bottle-feeding. The numbers of breast-feedings were adapted to the plasma Phe concentrations. At each feeding, either bottle- or breast-feeding, the child was allowed to drink until satiety. Data on metabolic control and growth during the first 6 months showed no statistically different results. The mean Phe concentration in the breast- fed group was 170 micro mol/l (range 137-243 micro mol/l) and in the formula- fed group 181 micro mol/l (range 114-257 micro mol/l). Compared to a routine where both bottle and breast are offered at each feeding, this new approach is more convenient for the parents and the child will be able to empty the breast, therefore drinking not only foremilk but also hindmilk.
Conclusion: the results suggest that this feeding protocol is safe in the strict treatment of otherwise healthy infants with phenylketonuria.